ener.hlp (Topic list)
RESUME without error (ERR: 20)
■ A RESUME statement was executed, but there is no active
  error handler.
 
■ Possible solution:
 
  • Isolate the error handler from linear execution of the
    program with END or EXIT SUB statements.
 
■ If you need additional help, move the cursor to a keyword
  and press F1 to open the Help window.